Large parts of Sitka will be without power for most of the night tonight (Thu 4-10-14) — or not, depending on what actions residents take to conserve electricity.
The Sitka Electric Department is installing the switches and transformers needed to operate a new backup generator, and will have to completely de-energize the Marine Street substation to allow linemen to perform the work safely.
But, as KCAW’s Robert Woolsey reports, the Department has a trick up its sleeve that will keep the electricity on at most homes, as long as we power off our big appliances.
The power outage is scheduled to begin at midnight, and last six hours. Unlike most outages in Sitka, when a tree falls on one of the main transmission lines, there will actually be plenty of power — just no way to get it around to everyone.
The Marine Street substation will be taken offline during the installation work. Utility director Chris Brewton says technicians will take the circuits normally fed by Marine Street, and tie them into the Jarvis substation — and “backfeed” power to all of Sitka.
It’s a pretty technical maneuver, but might sound familiar to backyard electricians.
“Putting a jumper in place to connect two circuits together. Yeah, exactly.”
The problem is: With one substation offline, Sitka will have about half the available power it usually does. Around 9 or 10 megawatts. A typical load during the middle of the night, though, might be 12 to 14 megawatts — so we’ll come up short.
Brewton says there are some strategies to bring the load down for this one night.
“We’re taking our interruptible loads offline, our high school boilers and that stuff. We’re also asking customers that have emergency generators to go on their generator, and help relieve some of that system load. The objective is that if we can get everyone to conserve that still remains energized, we may have enough power to keep everybody in power and not turn anyone off.”
Customers who don’t have interruptible loads or emergency generators — which is practically everybody — can also help.
“The biggest thing probably is to turn off your hot water heater. I realize that’s going to be a pain because you turn it off at midnight and you get up at six in the morning, it’s going to be cold. Turn off your hot water heater, don’t do your laundry, and don’t decide to cook your Thanksgiving dinner.”
Or don’t cook Thanksgiving dinner between midnight and 6 AM on Friday morning, that is.This work is being done in preparation for installing Sitka’s new Titan 130 diesel turbine — which will supplement the two backup generators already in place at the Jarvis Street substation.
The Titan 130 is a jet turbine. It looks like something that should be attached to the bottom of an Apollo rocket.
And Brewton says it feels like it belongs on a rocket.
Brewton — It is really impressive. The exhaust stack on this thing is seven feet in diameter. It’s huge.
KCAW — Is it like standing behind a 737 at takeoff?
Brewton — It absolutely is, if not worse!
The new turbine is part of the overall upgrade to Sitka’s electrical system, and is being funded in the same bond package paying for the Blue Lake hydro expansion. It’s scheduled to go into service later this summer.